"Invisible" bike helmet

Two Swedish women have come up with an "invisible" bike helmet. To spoil the video a bit, it is sort of a combination of automotive airbag and one of the avalanche rescue bags. Looks like a 1-time use thing. Don't think it would work for climbing helmets, though.

Hard shell bike helmets are a one time use. Any hard fall and you throw them away. While this inflatable may protect your noggin, the designers say it is less restrictive than a hard shell. However, even though there is nothing on your head, you still have a big donut around your neck. As well, the price is quite high. I'll stick with a hard shell.